Porous structures produced by additive layer manufacturing

ABSTRACT

A three-dimensional structure is formed when layers of a material are deposited onto a substrate and scanned with a high energy beam to at least partially melt each layer of the material. Upon scanning the layers at predetermined locations a tube device having a first tube and a second tube intersected with the first tube is formed.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims the benefit of the filing date of U.S.Provisional Patent Application No. 62/520,221, filed Jun. 15, 2017, thedisclosure of which is hereby incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates generally to preparing porous structures,and in particular to the preparation of mesh structures by way ofadditive manufacturing.

BACKGROUND OF THE INVENTION

The field of free-form fabrication has seen many important recentadvances in the fabrication of articles directly from computercontrolled databases. These advances, many of which are in the field ofrapid manufacturing of articles such as prototype parts and mold dies,have greatly reduced the time and expense required to fabricatearticles. This is in contrast to conventional machining processes inwhich a block of material, such as a metal, is machined according toengineering drawings.

Examples of modern rapid manufacturing technologies include additivelayer manufacturing (ALM) techniques such as electron beam melting,selective laser sintering (SLS), selective laser melting (SLM), andother three-dimensional (3-D) processes. When employing thesetechnologies, articles are produced in layer-wise fashion from alaser-fusible powder that is dispensed one layer at a time. The powderis sintered in the case of SLS technology and melted in the case of SLMtechnology, by the application of laser energy that is directed inraster-scan fashion to portions of the powder layer corresponding to across section of the article. After the sintering or melting of thepowder on one particular layer, an additional layer of powder isdispensed, and the process repeated, with sintering or melting takingplace between the current layer and the previously laid layers until thearticle is complete. In one example, a high energy beam is emitted froma beam-generating apparatus to heat metal powder sufficiently to sinterand preferably to at least partially melt or fully melt the metalpowder. High energy beam equipment for manufacturing such structures maybe one of many commercially available. The beam generation equipment mayalso be a custom-produced laboratory device. Detailed descriptions ofthe SLS technology may be found in U.S. Pat. Nos. 4,863,538, 5,017,753,5,076,869, and 4,944,817, the entire disclosures of which areincorporated by reference herein. Similarly, a detailed description ofthe use of SLM technology may be found in U.S. Pat. No. 7,537,664 (“the'664 Patent”), the disclosure of which is incorporated by referenceherein. The SLM and SLS technologies have enabled the direct manufactureof solid or porous three-dimensional articles of high resolution anddimensional accuracy from a variety of materials including wax, metaland metal alloys, metal powders with binders, polycarbonate, nylon,other plastics and composite materials, such as polymer-coated metalsand ceramics.

Other non-powder based additive manufacturing technologies are alsoknown to produce high resolution and dimensionally accurate articles.For example, in fused filament fabrication (FFF) or Plastic Jet Printing(PJP), strands of molten material are extruded from a nozzle to formlayers onto a substrate in which the material hardens upon extrusion.Using digital light processing (DLP), photosensitive resin plastic iscured by light and built layer by layer from the bottom-up or a vat ofliquid polymer is exposed to balanced levels of ultraviolet light andoxygen to produce a part often from the top-down. In inkjet 3D printing,a liquid binding material is selectively deposited across a thin layerof a powder and the process is repeated in which each new layer isadhered to the previous layer.

The invention claimed in the '664 Patent is one of several commonlyowned by Howmedica Osteonics Corporation that relate to the additivemanufacturing area. For instance, U.S. Pat. Appl. Publ. Nos.2006/0147332 A1 (“the '332 Publication”), U.S. Pat. No. 9,456,901 (“the'901 Patent”), U.S. Pat. No. 8,992,703 (“the '703 Patent”), U.S. Pat.No. 9,135,374 (“the '374 Patent”), and U.S. Pat. No. 9,180,010 (“the'010 Patent”), the entire disclosures of which are hereby incorporatedby reference herein, have taught the generation and organization of apopulation of porous geometry, a mathematical representation of theportion of geometry of the porous structure to be built within a regiondefined by a predetermined unit cell or imaginary volume, to fill andform a predetermined build geometry, i.e., a model build structure,which may be used to produce a near net-shape of an intended poroustissue in-growth structure. The predetermined build geometry, or overallcomputer-aided design (CAD) geometry, may refer to the mathematical orpictorial representation (such as that on a computer display) of theintended physical structure to be manufactured. In the case of physicalcomponents that include both porous material and solid material, thepredetermined build geometry may be an assembly of solid and porous CADvolumes that define the outer boundaries of the respective solid andporous materials intended to be manufactured. Furthermore, theseapplications teach the randomization of the position of interconnectednodes, or points of intersection between two struts or between a strutand a substrate, that define each of the porous geometries whilemaintaining the interconnectivity between the nodes. As further taughtin these applications, such randomization may be accomplished bychanging the coordinate positions of the nodes, in the x, y, and zdirections of a Cartesian coordinate system, to new positions based on adefined mathematical function.

During surgical operations on one or more bones, orthopedic implants aregenerally adhered to a bony surface by bone cement. Even properpreparation of delivery of bone cement to a smooth bony surface canresult in aseptic loosening of the implant and cement over time,especially when filling large void spaces such as in the proximal tibiaand distal femur, requiring a revision surgery to be performed. Currentimplants, which typically require the use of biocompatible materialssuch as titanium, used to retain bone cement lack flexibility and aredifficult to shape for a proper fit in a non-uniform space. Suchimplants are non-porous and thus lack limited surface area for contactwith bone. Implants produced using ALM techniques have been built withstrong scaffolds, but such implants are too rigid to allow for adequatedeformation to fill void spaces created by bone degradation.

Endoprosthetics is another area in which durable flexible structures,such as stents and stent grafts, are desirable. For example, vascularendoprosthetics, which are on the scale of microns and reasonablycomplex structures, are generally tubular expandable structures foropening and improving blood flow through arteries blocked by fattybuildup. Such devices are typically deployed and expanded by a deliverydevice or a balloon inserted through a catheter. In some instances, anendoprosthesis is needed to permit blood flow through branching bloodvessels. Customized endoprosthetics have been developed for thesesituations in which a patient-specific stent or a stent based on a 3Dmodel is prepared by fabricating a flexible mold using additivemanufacturing, forming the endoprosthetic around the mold, and thenremoving the mold. However, the use of such molds creates waste both interms of physical waste as well as the time to prepare these prostheses.

Thus, a new method is needed to create flexible structures which stillprovide mechanical strength to resist tensile and compressive forces,especially impact forces applied to bone and orthopedic implants, aswell as to create complex flexible structures with reducedpost-processing steps.

BRIEF SUMMARY OF THE INVENTION

In accordance with an aspect, a three-dimensional structure may beformed. In forming the three-dimensional structure, a first layer of amaterial may be deposited onto a substrate. A first layer of thematerial may be scanned with a high energy beam to at least partiallymelt the first layer of the material. Successive layers of the materialmay be deposited onto the first layer. Each of the successive layers ofthe material may be scanned with the high energy beam at predeterminedlocations to form at least a first segment overlapping a second segmentand underlapping a third segment.

In some arrangements, any number of the segments may be a curvilinearsegment. In some arrangements, any number of the segments may be arectilinear segment. In some arrangements, any number of the segmentsmay include both curvilinear and rectilinear portions.

In some arrangements, the three-dimensional structure may be in the formof a mesh defined by a weave pattern or a chain-link pattern.

In some arrangements, the material may be any one or any combination oftitanium, a titanium alloy, stainless steel, magnesium, a magnesiumalloy, cobalt, a cobalt alloy, a cobalt chrome alloy, nickel, a nickelalloy, tantalum, and niobium, polyethylene (PE) and variations thereof,polyetheretherketone (PEEK), polyetherketone (PEK), acrylonitrilebutadiene styrene (ABS), silicone, and cross-linked polymers,bioabsorbable glass, ceramics, and biological active materials includingcollagen/cell matrices.

In some arrangements, when scanning each of the successive layers atpredetermined locations a fourth segment spaced from the first segment,underlapping the second segment, and overlapping the third segment maybe formed.

In some arrangements, the second and third segments may be spaced fromeach other.

In some arrangements, the third segment may be the second segment suchthat the first segment underlaps and overlaps the second segment. Insuch arrangements, the second and third segments may form part of alink, which may form a portion of a chain mail structure.

In some arrangements, the first segment may completely surround thesecond segment. In such arrangements, the first segment may be a link ofa chain mail structure.

In some arrangements, the second segment may completely surround thefirst segment. In such arrangements, the second segment may be a link ofa chain mail structure.

In some arrangements, when scanning each of the successive layers atpredetermined locations a plurality of segments may be formed that maycompletely surround the first segment.

In some arrangements, a first additional layer of the material may bedeposited onto at least a predetermined location of the first segment.In some such arrangements, the first additional layer of the materialmay be scanned with the high energy beam at the predetermined locationof the first segment. In this manner, the first additional layer of thematerial may be fused to the first segment at the predeterminedlocation.

In some arrangements, successive additional layers of the material maybe deposited onto the first additional layer. In some such arrangements,each of the successive additional layers may be scanned with the highenergy beam at predetermined locations. In this manner, at least a firstadditional segment may be formed overlapping a second additional segmentand underlapping a third additional segment in which the firstadditional segment may be fused to at least the first segment at thepredetermined location of the first segment.

In some arrangements, the third additional segment may be the secondadditional segment such that the first additional segment underlaps andoverlaps the second additional segment. In such arrangements, the secondand third segments may form part of a link, which may form a portion ofa chain mail structure.

In some arrangements, when scanning each of the successive additionallayers at predetermined locations, a fourth additional segment spacedfrom the first additional segment, underlapping the second additionalsegment, and overlapping the third additional segment may be formed.

In some arrangements, when depositing the first additional layer of thematerial, the first additional layer of the material may be furtherdeposited onto predetermined locations of the second, third, and fourthsegments. In some such arrangements, when scanning the first additionallayer of the material with the high energy beam, the first additionallayer may be fused to each of the second, third, and fourth segments atthe respective predetermined locations of the second, third, and fourthsegments.

In some arrangements, successive additional layers of the material maybe deposited onto the first additional layer. In some such arrangementsin which successive additional layers of the material may be depositedonto the first additional layer, each of the successive additionallayers may be scanned with the high energy beam at predeterminedlocations to form at least one symbol. In some such arrangements formingat least one symbol, any number of such symbols may be fused to at leastthe first segment at the predetermined location of the first segment. Insome such arrangements forming at least one symbol, any number of suchsymbols may be an alphanumeric character.

In some arrangements, when scanning each of the successive layers atpredetermined locations, at least one barb may be formed. Any number ofsuch barbs may extend from any one or any combination of the first,second, and third segments.

In some arrangements, when scanning each of the successive layers atpredetermined locations, a first series of segments extending in a firstdirection and a second series of segments extending in a seconddirection transverse to the first direction may be formed. The firstseries of segments may include the first segment. The second series ofsegments may include the second and third segments. Some or all of thesegments of the first series of segments may overlap a plurality ofsegments of the second series of segments and may underlap anotherplurality of segments of the second series of segments such that thefirst and second series of segments form a first mesh.

In some arrangements, the first mesh may be a flexible sheet. The firstmesh may be foldable such that a substantially planar first portion ofthe first mesh lies in a plane at an angle of up to substantially 180degrees to a plane in which a substantially planar second portion of thefirst mesh lies.

In some arrangements, the first mesh may be a flexible sheet formed inthe shape of a cone or a frustum of a cone.

In some arrangements, the first mesh may define a pocket. The pocket ofthe first mesh may be stamped to form a cavity in the pocket. In somesuch arrangements, when the first mesh is stamped by a tool, a bottomsurface of the cavity of the first mesh may conform to a bottom surfaceof the tool. When the first mesh is stamped by a tool having protrusionsextending from a flat base, a bottom surface of the first mesh may havecorresponding protrusions extending from the bottom surface upon beingstamped by the tool.

In some arrangements, when scanning each of the successive layers of thematerial at predetermined locations, a third series of segmentsextending in a third direction and a fourth series of segments extendingin a fourth direction transverse to the third direction may be formed.In some such arrangements, each of the segments of the third series ofsegments may overlap a plurality of segments of the fourth series ofsegments and may underlap a plurality of segments of the fourth seriesof segments. In this manner, the third and fourth series of segments mayform a second mesh. In some such arrangements, when scanning each of thesuccessive layers at predetermined locations, at least one segment maybe formed that underlaps and overlaps at least one segment of the firstand second series of segments and at least one segment of the third andfourth segments such that the first and second meshes may be rotatablyattached to each other.

In some arrangements, the first and the third directions are the same.In the same or in other arrangements, the second and the fourthdirections are the same.

In some arrangements, either one or both of the first and the secondmeshes may have a profile substantially in the form of any one or anycombination of a square, a rectangle, a circle, and a triangle.

In some arrangements, the first and the second meshes may have edgesadjacent and substantially parallel to each other such that uponrotation of either of the edges about the other edge, the edges do notinterfere with such rotation.

In some arrangements, pluralities of the segments of the first andsecond series of segments may define a bore through a thickness of thescanned successive layers of the material.

In some arrangements, when scanning each of the successive layers atpredetermined locations an outer ring, and wherein ends of pluralitiesof the segments of the first and second series of segments are fused toan outer perimeter of the outer ring, an inner perimeter opposite theouter perimeter of the outer ring defining the bore through thethickness of the scanned successive layers of the material.

In some arrangements, when scanning each of the successive layers atpredetermined locations, an inner ring concentric with the outer ringmay be formed. In some such arrangements when scanning each of thesuccessive layers at predetermined locations, segments fused to andbetween the inner perimeter of the outer ring and an outer perimeteropposite an inner perimeter of the inner ring may be formed. In sucharrangements, the inner perimeter of the inner ring may define the borethrough the thickness of the scanned successive layers of the material.

In some arrangements, when scanning each of the successive layers atpredetermined locations a stud or rivet may be formed. In some sucharrangements, ends of pluralities of the segments of the first andsecond series of segments may fused to the perimeter of the stud orrivet.

In some arrangements, when scanning each of the successive layers atpredetermined locations, a third series of segments extending in a thirddirection and a fourth series of segments extending in a fourthdirection transverse to the third direction may be formed. In some sucharrangements, each of the segments of the third series of segments mayoverlap a plurality of segments of the fourth series of segments and mayunderlap a plurality of segments of the fourth series of segments. Inthis manner, the third and fourth series of segments may form a secondmesh. In some such arrangements, when scanning each of the successivelayers at predetermined locations, a solid section may be formed. Thesolid section may be fused to each of the first and second meshes. Inthis manner, the solid section may be movable relative to portions ofeach of the first and second meshes.

In some arrangements, when scanning each of the successive layers atpredetermined locations a hook extending from the first segment may beformed.

In some arrangements, the first segment may be fused to at least one ofthe second and the third segments.

In some arrangements, the first segment may be fused to only one of thesecond and the third segments.

In accordance with another aspect, bone ingrowth may be facilitated. Infacilitating such bone ingrowth, a porous tissue ingrowth structure maybe formed in the shape of a mesh implant. In forming the mesh implant, afirst layer of a material may be deposited onto a substrate. A firstlayer of the material may be scanned with a high energy beam to at leastpartially melt the first layer of the material. Successive layers of thematerial may be deposited onto the first layer. Each of the successivelayers of the material may be scanned with the high energy beam atpredetermined locations to form at least a first segment overlapping asecond segment and underlapping a third segment. The mesh implant may beshaped into a desired shape. The mesh implant may have a porosity topromote bone ingrowth. The mesh implant may be placed against a boneportion. A bone implant may be placed against bone cement such that thebone cement contacts both the mesh implant and the bone implant. Themesh implant may prevent contact of the bone cement with bone ingrowninto the mesh implant.

In accordance with another aspect, a three-dimensional structure may beformed. In forming the three-dimensional structure, a first layer of amaterial may be formed over at least a substrate. The first layer of thematerial may be scanned with a high energy beam to form a first pattern.The first pattern may include a first portion (a1) of a first solidportion (A). A second layer of the material may be deposited over thefirst layer of the material. The second layer of the material may bescanned with a high energy beam to form a second pattern. The secondpattern may include a first portion (b1) of a second solid portion (B).A third layer of the material may be deposited over at least asubstrate. The third layer of the material may be scanned with a highenergy beam to form a third pattern. The third pattern may include asecond portion (a2) of the first solid portion (A). A fourth layer ofthe material may be deposited over at least the second layer of thematerial. The fourth layer of the material may be scanned with a highenergy beam to form a fourth pattern. The fourth pattern may include athird portion (a3) of the first solid portion (A). A fifth layer of thematerial may be deposited over at least the third layer of the material.The fifth layer of the material may be scanned with a high energy beamto form a fifth pattern. The fifth pattern may include a first portion(c1) of a third solid portion (C). A sixth layer of the material may bedeposited over at least the fifth layer of the material. The sixth layerof the material may be scanned with a high energy beam to form a sixthpattern. The sixth pattern may include a fourth portion (a4) of thefirst solid portion (A). The first, second, third, and fourth portionsof the first solid portion (A) may be attached to each other such thatthe first solid portion (A) at least partially wraps around the secondsolid portion (B) and the third solid portion (C).

In some arrangements, at least some of the second, third, fourth, andfifth layers may be the same layer.

In some arrangements, the second solid portion (B) is the same as thethird solid portion (C) such that the first solid portion (A) forms alink.

In some arrangements, the first and third layers may be the same layersuch that the third pattern is part of the first pattern. In sucharrangements, the first pattern may further include a first portion (d1)and a second portion (d2) of a fourth solid portion (D). The firstportion (d1) and the second portion (d2) of the fourth solid portion (D)may be offset from the first portion (a1) and the second portion (a2) ofthe first solid portion (A) within the first pattern. In sucharrangements, the second and fifth layers may be the same layer suchthat the fifth pattern is part of the second pattern. In sucharrangements, the first portion (b1) of the second solid portion (B) andthe first portion (c1) of the third solid portion (C) may be offset fromeach other. In such arrangements, the fourth and sixth layers may be thesame layer such that the sixth pattern is part of the fourth pattern. Insuch arrangements, the fourth pattern may further include a thirdportion (d3) and a fourth portion (d4) of the fourth solid portion (D).In such arrangements, the third portion (d3) and the fourth portion (d4)of the fourth solid portion (D) may be offset from the third portion(a3) and the fourth portion (a4) of the first solid portion (A) withinthe fourth pattern. In such arrangements, the first, second, third, andfourth portions of the fourth solid portion (D) may be attached to eachother such that the fourth solid portion (A) weaves around the secondsolid portion (B) and the third solid portion (C) in the opposite mannerthat the first solid portion weaves around the second solid portion (B)and the third solid portion (C).

In some arrangements, at least one of the second portion (a2) and thethird portion (a3) of the first solid portion (A) may be fused to atleast one of the first portion (b1) of the second solid portion (B) andthe first portion (c1) of the third solid portion (C).

In accordance with another aspect, a non-transitory computer-readablestorage medium may have computer readable instructions of a programstored on the medium. The instructions, when executed by a processor,cause the processor to perform a process of preparing acomputer-generated model of a three-dimensional structure constructed ofunit cells. In performing the process, a computer-generated componentfile may be prepared. The computer-generated component file may includea porous CAD volume which may have a boundary. A space may be populated,by a processor, to include the porous CAD volume. The porous CAD volumemay be populated with unit cells. Each of the unit cells may bepopulated, by a processor, with at least one segment geometry to form aplurality of segment geometries. A first segment geometry of theplurality of segment geometries may overlap a second segment geometry ofthe plurality of segment geometries and underlap a third segmentgeometry of the plurality of segment geometries.

In accordance with another aspect, a tubular structure including a firsttube and a second tube may be formed. In forming the tubular structure,successive layers of a first material may be deposited. At least aportion of each of the deposited layers of the first material may be atleast partially melted at predetermined locations to form the firsttube. Successive layers of a second material may be deposited. At leasta portion of each of the deposited layers of the second material may beat least partially melted at additional predetermined locations to formthe second tube such that the second tube is attached to the first tubeat an intersection.

In some arrangements, the successively deposited layers of the first andthe second materials may be at least partially melted with a high energybeam. In some arrangements, a complete layer or complete layers ofeither or both of the first tube and the second tube may be formedduring a generally continuous operation, i.e., cycle, of thebeam-generating apparatus. The high energy beam may be emitted with apreset duty cycle and may have a preset dwell time during suchcontinuous operation. However, during such continuous operation a layerof the first tube, a layer of the second tube, or layers of both thefirst tube and the second tube, as the case may be, may be formed on thesame substrate. Generally, such layers will be formed within the sameplane which may be parallel to a substrate upon which the respectivefirst tube, second, or combination of the first tube and the second tubeare fabricated.

In some arrangements, either one or both of the first and the secondmaterials may be made of any one or any combination of plastic, metal,ceramic, and glass. In some arrangements, either one or both of thefirst and the second materials may be a superelastic metal alloy. Insome arrangements, the first material and the second material may be thesame material. In some arrangements, either one or both of the first andthe second materials may be powder.

In some arrangements, portions of a plurality of segments may be formedwhen the deposited layers of either one or both of the first and thesecond materials are at least partially melted. In some sucharrangements, the formed segments of the plurality of segments may beattached to at least one other formed segment of the plurality ofsegments at vertices to define a plurality of open cells. In some sucharrangements, the plurality of open cells may form a surface or surfacesof either one or both the first tube and the second tube. In somearrangements, the open cells may form a reticulated configuration. Insome arrangements, the open cells may be tessellated. In somearrangements, each of the plurality of the segments may have opposingends. In some arrangements, each of the open cells may be bounded by arespective closed perimeter defined by only attached pairs of segmentsof the plurality of segments. In some arrangements, some of the opencells may be larger than some of the other open cells. In somearrangements, a plurality of ends of the tubular structure may be formedwhen the deposited layers of either one or both of the first and thesecond materials are at least partially melted. In some sucharrangements, some segments of the plurality of segments between theends of the tubular structure may be attached to at most one othersegment of the plurality of segments. In some arrangements, a porous endof the tubular structure may be formed when the deposited layers of thefirst material is at least partially melted. In some such arrangements,the porous end may be defined by a plurality of the plurality ofsegments within a perimeter of the first tube. In some arrangements, afully dense region of the first material may be formed between opencells of the plurality of open cells in the first tube when thedeposited layers of the first material are at least partially melted. Insome such arrangements, the fully dense region may extend from the firsttube to the second tube such that the fully dense region is also in thesecond tube. In some such arrangements, the first material and thesecond material may be the same material. In some such arrangements, aperimeter of the fully dense region may have the same dimension as therespective closed perimeters of the open cells.

In some arrangements, the segments of the plurality of segments may havea diameter of less than 200 μm. In some such arrangements, the segmentsof the plurality of segments may have a diameter in the range from 10 to150 μm. In some arrangements, the first tube and the second tube mayshare segments of the plurality of segments at their intersection.

In some arrangements, projections extending from either one or both ofthe first tube and the second tube may be formed when the respectivedeposited layers of either one or both of the first and the secondmaterials are at least partially melted. In some such arrangements, atleast some of the projections may be curved struts.

In some arrangements, the first tube may define a central axis of thefirst tube. In some such arrangements, an end of the first tubeextending in a direction transverse to the central axis may be formedwhen the deposited layers of the first material are at least partiallymelted. In some such arrangements, only a portion of a perimeter of theend attaches to the first tube such that the end may either one or bothof form a hinge or be closable. In some arrangements, the end may besolid and may extend within and around an entirety of the perimeter ofthe first tube.

In some arrangements, at least one portion of the first tube and atleast one portion of the second tube may be formed when the depositedlayers of the first and the second materials are at least partiallymelted.

In some arrangements, either one or both of the first tube and thesecond tube may have a cross-section selected from the group consistingof a circle, an ellipse, a polygon, and an irregular shape. In somearrangements, the first tube may have varying cross-sections along afirst tube length of the first tube. In some such arrangements, thecross-sections of the first tube may define a plane perpendicular to acentral axis of the first tube. In some such arrangements, the secondtube may have varying cross-sections along a second tube length of thesecond tube. In some such arrangements, the cross-sections of the secondtube may define a plane perpendicular to a central axis of the secondtube.

In some arrangements, each separate at least partially melted layer ofthe first material to form the first tube may form a completecross-section of the first tube. In some arrangements, each separate atleast partially melted layer of the second material to form the secondtube may form a complete cross-section of the second tube. In some sucharrangements, the second material may be the same material as the firstmaterial such that each separate at least partially melted layer of thefirst material to form the first tube and each separate at leastpartially melted layer of the second material to form the second tubemay form a complete cross-section of both the first tube and the secondtube within a same at least partially melted layer.

In some arrangements, pathways defined by each of the first tube and thesecond tube may be in communication such that objects passing throughthe first tube may enter the second tube directly from the first tube.

In some arrangements, either one or both of the first tube and thesecond tube may have varying surface topologies.

In some arrangements, an additional material different from the firstmaterial may be deposited with or within at least one of the depositedlayers of the first material. In such arrangements, at least a portionof the deposited additional material may be at least partially melted atpredetermined marker locations to form radiopaque markers. In some sucharrangements, the radiopaque markers, upon formation of the first tubeand the second tube, may be either one or both of (i) at a surface ofeither one or both of the first tube and the second tube or (ii) extendfrom either one or both of the first tube and the second tube. As usedherein, the term “at a surface” means just below but exposed by thesurface, level with or along the surface, or just above but intersectingwith the surface unless otherwise indicated. In some such arrangements,the additional material may include a predetermined amount of platinumcorresponding to a desired level of radiopacity of the radiopaquemarkers.

In some arrangements, either one or both of the first tube and thesecond tube may be formed to interface with another medical device. Insome such arrangements, the medical device may be a catheter, anendoscope, or a platinum wire.

In some arrangements, a first dielectric layer may be formed onto an atleast partially melted layer of either one or both of the first materialand the second material after at least partially cooling such partiallymelted layer. In some such arrangements, a conductive material may bedeposited onto the formed dielectric layer. In some such arrangements,at least a portion of the deposited conductive material may be at leastpartially melted at predetermined locations to form a patternedconductive layer. In this manner, the patterned conductive layer, uponformation of the first tube and the second tube, may be on or may beembedded in either one or both of the first tube and the second tube. Insome such arrangements, the conductive layer may be made of any one orany combination of gold, copper, and platinum. In some arrangements, asecond dielectric layer may be formed onto the at least partially meltedconductive material after at least partially cooling the seconddielectric layer.

In some arrangements, the first material and the second material may bedeposited over a substrate. In some arrangements, e.g., in a “top-down”approach where formed layers may be suspended from an object carrier,later layers of the successively deposited layers that have been atleast partially melted may be below earlier such layers relative to theground.

In accordance with another aspect, a tubular structure including a firsttube and a second tube may be formed. In forming the tubular structure,a first layer of a material may be deposited onto a substrate. At leastpart of the first layer of the material may be at least partially meltedat predetermined locations. Successive layers of the material may bedeposited onto previous layers of the material. At least part of each ofthe successive layers of the material may be at least partially meltedat additional predetermined locations to form a first tube intersectedwith a second tube in which either one or both of the first tube and thesecond tube includes at least a first segment overlapping a secondsegment and underlapping a third segment.

In some arrangements, the third segment may be the second segment suchthat the first segment underlaps and overlaps the second segment. Insome such arrangements, the first segment may completely surround thesecond segment. In some such arrangements, the second segment maycompletely surround the first segment.

In accordance with another aspect, a tubular structure including a firsttube and a second tube may be formed. In forming the tubular structure,a first layer of a material may be deposited onto a substrate. At leastpart of the first layer of the material may be at least partially meltedat predetermined locations. Successive layers of the material may bedeposited onto previously deposited and at least partially melted layersof the material. At least part of each of the successive layers of thematerial may be at least partially melted at additional predeterminedlocations to form a first tube intersected with a second tube.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a functional diagram of a system in accordance with anembodiment;

FIGS. 2-4B are various views of three-dimensional model representationsof unit cells having wireframes located therein in accordance with otherembodiments;

FIG. 5 is a process flow diagram in accordance with another embodiment;

FIG. 6 is an example of a mesh sheet in accordance with anotherembodiment;

FIGS. 7A-7D are illustrative profile views of mesh sheets in accordancewith another embodiment;

FIG. 8 is an example of an application of the mesh sheet of FIG. 6 ;

FIGS. 9A and 9B are perspective views of a three-dimensional modelrepresentation of respective portions of a mesh sheet in accordance withan embodiment;

FIG. 9C is a perspective view of a three-dimensional modelrepresentation of a unit cell for use in preparing the three-dimensionalmodel representation of the portion of the mesh sheet of FIG. 9A;

FIGS. 10A-12C are views of applications of mesh sheets in accordancewith embodiments;

FIG. 13A is a perspective view of a three-dimensional modelrepresentation of a portion of a mesh sheet in accordance with anembodiment;

FIG. 13B is an example of an application of the mesh sheet of FIG. 13A;

FIGS. 14A-15 are perspective views of three-dimensional modelrepresentations of a portion of mesh sheets in accordance with anembodiment;

FIG. 16 is an example of a mesh sheet in accordance with an embodiment;

FIGS. 17A-17C are examples of applications of mesh sheets in accordancewith embodiments;

FIGS. 18A-18C are views of an application of mesh sheets in accordancewith embodiment;

FIGS. 19A and 19B are perspective and side views of a mesh sheet inaccordance with an embodiment;

FIG. 19C is a perspective view of a tool for use with the mesh sheet ofFIGS. 19A and 19B in accordance with an embodiment;

FIGS. 19D and 19E are perspective and side views of the mesh sheet ofFIGS. 19A and 19B after deformation of the mesh sheet by the tool ofFIG. 19C in accordance with an embodiment;

FIG. 20A is a side view of a tool for use with the mesh sheet of FIGS.19A and 19B in accordance with an embodiment;

FIG. 20B is a side view of the mesh sheet of FIGS. 19A and 19B afterdeformation of the mesh sheet by the tool of FIG. 20A in accordance withan embodiment;

FIG. 21 is a perspective view of an application of the deformed meshsheets of either of FIGS. 19D and 20B;

FIG. 22A is a perspective view of a tube device in accordance with anembodiment;

FIG. 22B is an elevation view of the tube device of FIG. 22A duringfabrication of the tube device;

FIG. 23 is a process flow diagram of a process of forming a porousstructure in accordance with an embodiment;

FIGS. 24A-24C are perspective views of portions of tube devices inaccordance with other embodiments;

FIG. 25 is an elevation view of a portion of a tube device in accordancewith another embodiment;

FIGS. 26-29 are perspective views of portions of tube devices inaccordance with other embodiments; and

FIG. 30 is a process flow diagram of a process of forming a porousstructure.

DETAILED DESCRIPTION

This invention relates generally to generating computer models ofthree-dimensional structures. These models may be used to prepare poroustissue in-growth structures in medical implants and prostheses. Themodels may include features corresponding to tangible structures.

FIG. 1 depicts system 105 that may be used, among other functions, togenerate, store and share three-dimensional models of structures. System105 may include at least one server computer 110, first client computer115, and in some instances, at least second client computer 130. Thesecomputers may send and receive information via network 140. For example,a first user may generate a model at first client device 115. The modelmay then be uploaded to server 110 and distributed via network 140 tosecond client computer 130 for viewing and modification by a seconduser, who or which may be the first user.

Network 140, and intervening communication points, may comprise variousconfigurations and protocols including the Internet, World Wide Web,intranets, virtual private networks, wide area networks, local networks,private networks using communication protocols proprietary to one ormore companies, Ethernet, WiFi and HTTP, and various combinations of theforegoing. Such communication may be facilitated by any device capableof transmitting data to and from other computers, such as modems (e.g.,dial-up, cable or fiber optic) and wireless interfaces. Although only afew devices are depicted in FIG. 1 , a system may include a large numberof connected computers, with each different computer being at adifferent communication point of the network.

Each of computers 110, 115, and 130 may include a processor and memory.For example, server 110 may include memory 114 which stores informationaccessible by processor 112, computer 115 may include memory 124 whichstores information accessible by processor 122, and computer 130 mayinclude memory 134 which stores information accessible by processor 132.

Each of processors 112, 122, 132 may be any conventional processor, suchas commercially available CPUs. Alternatively, the processors may bededicated controllers such as an ASIC, FPGA, or other hardware-basedprocessor. Although shown in FIG. 1 as being within the same block, theprocessor and memory may actually comprise multiple processors andmemories that may or may not be stored within the same physical housing.For example, memories may be a hard drive or other storage media locatedin a server farm of a network data center. Accordingly, references to aprocessor, memory, or computer will be understood to include referencesto a collection of processors, memories, or computers that may or maynot operate in parallel.

The memories may include first part storing applications or instructions116, 126, 136 that may be executed by the respective processor.Instructions 116, 126, 136 may be any set of instructions to be executeddirectly (such as machine code) or indirectly (such as scripts) by theprocessor. In that regard, the terms “applications,” “instructions,”“steps” and “programs” may be used interchangeably herein.

The memories may also include second part storing data 118, 128, 138that may be retrieved, stored or modified in accordance with therespective instructions. The memory may include any type capable ofstoring information accessible by the processor, such as a hard-drive,memory card, ROM, RAM, DVD, CD-ROM, write-capable, and read-onlymemories or various combinations of the foregoing, where applications116 and data 118 are stored on the same or different types of media.

In addition to a processor, memory and instructions, client computers115, 130, 131, 133 may have all of the components used in connectionwith a personal computer. For example, the client computers may includeelectronic display 150, 151 (e.g., a monitor having a screen, atouch-screen, a projector, a television, a computer printer or any otherelectrical device that is operable to display information), one or moreuser inputs 152, 153 (e.g., a mouse, keyboard, touch screen and/ormicrophone), speakers 154, 155, and all of the components used forconnecting these elements to one another.

Instructions 126, 136 of the first and second client devices 115, 130may include building applications 125, 135. For example, the buildingapplications may be used by a user to create three-dimensionalstructures, such as those described further herein. The buildingapplications may be associated with a graphical user interface fordisplaying on a client device in order to allow the user to utilize thefunctions of the building applications.

A building application may be a computer-aided design (CAD) 3-D modelingprogram or equivalent as known in the art. Available CAD programscapable of generating such a structure include Autodesk® AutoCAD®, Creo®by Parametric Technology Corporation (formerly Pro/Engineer), SiemensPLM Software NXTM (formerly Unigraphics NX), SOLIDWORKS® by SolidWorksCorporation, and CATIA® by Dassault Systèmes. Such structures may bethose described in the '421 Application.

Data 118, 128, 138 need not be limited by any particular data structure.For example, the data may be stored in computer registers, in arelational database as a table having a plurality of different fieldsand records, or XML documents. The data also may be formatted into anycomputer-readable format such as, but not limited to, binary values,ASCII or Unicode. Moreover, the data may comprise any informationsufficient to identify the relevant information, such as numbers,descriptive text, proprietary codes, pointers, references to data storedin other memories (including other network locations) or informationthat is used by a function to calculate the relevant data. For example,data 128 of first client device 115 may include information used bybuilding application 125 to create three-dimensional models.

In addition to the operations described above and illustrated in thefigures, various other operations will now be described. It should beunderstood that the following operations do not have to be performed inthe precise order described below. Rather, various steps may be handledin a different order or simultaneously. Steps also may be omitted oradded unless otherwise stated herein.

An overall three-dimensional representation of a component may first begenerated by preparing a CAD model. This overall CAD model may becomprised of one or more distinct CAD volumes that are intended to bemanufactured as either solid or porous physical structures, i.e.,constructs.

Solid CAD volumes, which correspond to manufactured solid physicalstructures, can be sliced into layers of a predetermined thickness readyfor hatching, re-merging with the porous volume (post-latticegeneration), and subsequent manufacture.

Porous CAD volumes, such as porous CAD volume 100 shown in the exampleof FIG. 2 and which correspond to manufactured porous geometries, can beprocessed using bespoke software. As in the example of FIG. 2 , a porousgeometry is made up of one or more segments 110, 120 organized withintessellated unit cells 105. Many designs are possible for a porousgeometry which allows the porous geometry to impart various strength,surface, and/or other characteristics into the porous CAD volume. Forexample, porous geometries can be used to control the shape, type,degree, density, and size of porosity within the structure. Such porousgeometry shapes can be dodecahedral, octahedral, tetrahedral (diamond),as well as other various shapes.

As further shown in FIG. 2 , porous CAD volume 100 is formed by aplurality of unit cells 105 which each contain curvilinear segmentgeometry 110 and curvilinear segment geometry 120. Curvilinear segmentgeometry 110 within each unit cell 105 extend from an end 111 thereoflocated at a center of a lower left edge of the unit cell to an end 112thereof located at a center of an upper right edge of the unit cell, andcurvilinear segment geometries 120 within each unit cell 105 extend froman end 121 thereof located at a center of an upper left edge of the unitcell to an end 122 thereof located at a center of a lower right edge ofthe unit cell.

Unit cells 105 are adjacent to each other such that end 112 ofcurvilinear segment geometry 110 within one unit cell 105 abuts, andindeed is the same as, end 121 of curvilinear segment geometry 120within adjacent unit cell 105 and such that end 122 of curvilinearsegment geometry 120 within one unit cell 105 abuts, and is the same as,end 111 of curvilinear segment geometry 110 within adjacent unit cell105. As shown, curvilinear segment geometry 110 within each unit cell105 curves around curvilinear segment geometry 120 within the same unitcell. In this manner, a connected pair of curvilinear segment geometry110 and curvilinear segment geometry 120 within adjacent unit cells 105overlaps the other connected pair of curvilinear segment geometry 110and curvilinear segment geometry 120 within the same adjacent unitcells.

As shown in FIG. 3 , porous CAD volume 100A includes unit cells 105formed adjacent to other unit cells 105 such that ends of curvilinearsegment geometries 110, 120 of one unit cell abut an end of the othercurvilinear segment geometry of respective curvilinear segmentgeometries 110, 120 of the adjacent unit cell. As further shown, aplurality of barb geometries 135 extend from various ends 111, 112 ofcurvilinear segment geometries 110 and ends 121, 122 of curvilinearsegment geometries 120 such that barb geometries 135 extend transverselyacross the curvilinear segment geometries 110, 120 corresponding to therespective ends. In this manner, a plurality of unit cells 105 may betessellated to form the porous CAD volume 100A.

When used for medical implants, barb geometries, such as barb geometries135, may correspond to physical barbs that encourage directionalfixation of the implants. In such applications, the barbs may vary inspacing and length. Such barbs may be but are not limited to being onthe order of 0.6-1.2 mm in length. Any directional barb hairs, branches,rods, and beads also may be incorporated into a porous mesh structure toencourage directional fixation with bone. As barb geometries, such asbarb geometries 135, may be placed at any predetermined or, conversely,at randomly selected positions along segment geometries of a porous CADvolume, barbs corresponding to the barb geometries may be placed at anysuch corresponding positions on segments corresponding to segmentgeometries.

Referring now to FIG. 4A, porous CAD volume 200A formed by tessellationof a plurality of unit cells 205A, 206A each containing linear segmentgeometry 210A and curvilinear segment geometry 220A. As in this example,opposing ends 211A, 212A of linear segment geometry 210A within eachunit cell 205A, 206A may extend from centers of opposite faces of theunit cell, and curvilinear segment geometry 220A of each unit cell 205Amay extend from an end 221A thereof located at a center of an upperfront edge of the unit cell, around the linear segment geometry, and toan end 222A thereof located at a center of an upper rear edge of theunit cell. In this manner, segment geometries 210A, 220A form portionsof mesh geometry.

A plurality of unit cells 205A and separately a plurality of unit cells206A may be adjacent to each other such that end 221A of curvilinearsegment geometry 210A of one unit cell 205A, 206A abuts end 222A ofcurvilinear segment geometry 220A of respective adjacent unit cell 205A,206A. As further shown, the plurality of unit cells 206A may be invertedrelative to the plurality of unit cells 205A, and end 211A of linearsegment geometry 210A of one unit cell 205A may abut end 212A of linearsegment geometry 210A of respective adjacent unit cell 206A. In thismanner, curvilinear segment geometries 210A of each of the plurality ofunit cells 205A, 206A and the linear geometries 210A of each of theplurality of unit cells 205A, 206A may collectively form a woven meshgeometry. As in the example shown, the linear segment geometries 210A ofthe plurality of unit cells 205A, 206A may all be parallel to eachother.

Referring to FIG. 4B, porous CAD volume 200B is formed by tessellationof a plurality of unit cells 205B, 206B each containing curvilinearsegment geometry 210B in which curvilinear segment geometry 210B of unitcell 206B is inverted relative to curvilinear segment geometry 210B ofunit cell 205B. As in this example, opposing ends 211B, 212B ofcurvilinear segment geometry 210B of each unit cell 205B, 206B mayextend from opposite corners of the respective unit cells. Unit cells205B may be diagonal from each other such that they share only onecommon edge, and similarly, unit cells 206B may be diagonal from eachother such that they share only one common edge. In this manner, ends212B of curvilinear segment geometries 210B of each of a first set ofunit cells 205B, 206B may abut ends 211B of curvilinear segmentgeometries 210B of each of a second set of unit cells 205B, 206B locateddiagonally to the first set of the unit cells. In this manner, aconnected pair of curvilinear segment geometry 210B of diagonallylocated set of unit cells 205B overlaps a connected pair of curvilinearsegment geometry 210B of diagonally located set of unit cells 206B toform mesh geometry. As shown, such mesh geometry may be in the form of awoven mesh.

A larger mesh geometry may be formed by adding further sets of the fourunit cells 205B, 206B to each of the four sets of two side faces 213,214 of adjoining unit cells 205B, 206B, i.e., to the side faces 213, 214around the circumference of the four-cubes shown in the illustration ofFIG. 4B. In alternative arrangements, the mesh geometry defined by thefour curvilinear segments 210B of the four unit cells 205B, 206B shownin FIG. 4B may be arranged in a single unit cell, which may betessellated to form a porous CAD volume.

Other variations of unit cells 105 and 205, 206 in which at least onesegment geometry defining the unit cell is curved or includes angledportions, which may be in the shape of a “V,” “W” or other combinationof linear portions, such that the segment geometry curves or wrapsaround another segment geometry of the unit cell are within the scope ofthe present technology. Such variations could also be used to formporous CAD volumes. In other arrangements, a CAD model may be generatedwithout forming unit cells and thus without tessellation of featureswithin the unit cells. Such CAD models created without tessellated unitcells may be in the form of a woven mesh, i.e., cross-hatch, geometrywith overlapping and underlapping strips, i.e., ribbons. In somealternative arrangements, woven mesh geometries may have a plurality ofadjacent segment geometries or set of segment geometries that overlapand underlap the same transverse corresponding segment geometries or setof segment geometries, e.g., in the form of a “double weave.” In othervariations of forming mesh geometries, the ends of the segment may be atany location within a unit cell so long as the segment geometries ofeach unit cell, alone or in combination with segment geometries ofadjacent unit cells overlap and underlap segment geometries within thesame unit cell or within adjacent unit cells, i.e., in a manner similarto the overlapping and underlapping of the segment geometries shown inFIGS. 4A and 4B. For example, ends may be but are not limited to beingat corners of unit cells, centers of edges of unit cells, and thecenters of faces of unit cells. In some arrangements, a percentage ofthe junctions where segment geometries of a porous CAD volume overlapeach other may be fused together. When fusion of such junctions isunevenly distributed, anisotropy in a physical mesh structurecorresponding to a porous CAD volume may be created.

Referring to FIG. 5 , in an example of preparing a porous CAD volume ofsegment geometries, a computer-generated component file is prepared at ablock 191. The component file includes a porous CAD volume with aboundary having at least one predefined portion. At a block 192, a spacethat includes the porous CAD volume is populated, by a processor, withunit cells. Such a space may be defined by sets of coordinates, such asCartesian, polar, or spherical coordinates. At a block 193, the unitcells are populated with one or more segment geometries to form aplurality of segment geometries. As further shown at block 193, a firstcurvilinear segment geometry of the plurality of segment geometriesoverlaps a second segment geometry of the plurality of segmentgeometries and underlaps a third segment geometry of the plurality ofsegment geometries. In this manner, a computer-generated model of athree-dimensional structure constructed of segment geometries isprepared.

The above-described model geometries can be visualized in a number ofways, including but not limited to by voxelating the sliced output filesfrom bespoke software that is being applied in an ALM machine. Utilizingdeveloped algorithms and the output files, the data may be fed into acommercial software package, e.g., MATLAB® by MathWorks, Inc., and theimages produced can be interpreted. At an optional block 194, a tangiblethree-dimensional structure having a shape corresponding to thecomputer-generated model may be produced. The shape of thethree-dimensional structure may be in the form of a mesh structure, suchas a mesh implant.

The approaches for generating the three-dimensional models describedherein may be used for building various tangible structures andsurfaces, specifically structures and surfaces for medical implants.Upon completion of a CAD model including the porous geometries and anysolid geometries that may be connected to the porous geometries, anintended physical structure may be formed directly onto a substrateusing a layered additive manufacturing process, including but notlimited to electron beam melting (EBM), selective laser sintering (SLS),selective laser melting (SLM), and blown powder fusion for use withmetal powders. Techniques such as but not limited to SLS,three-dimensional inkjet printing (3DP), stereolithography (SLA), andfused filament fabrication (FFF) may be used with polymer powders orstrands to produce plastic constructs. Cellular scaffolds may be formedusing bioplotters or 3DP. Although a brief summary follows, many detailsof a process of melting powdered metal are given in the '332 Publicationand '901 Patent. In an example of constructing a tangible structure froma model build geometry using metal powder, a layer of metal powder maybe deposited onto a substrate. The substrate may be a work platform, asolid base, or a core, with the base or core being provided to possiblybe an integral part of the finished product.

The metal powder may be but is not limited to being made from anycombination of titanium, a titanium alloy, stainless steel, magnesium, amagnesium alloy, cobalt, a cobalt alloy including a cobalt chrome alloy,nickel, a nickel alloy including a nickel titanium alloy such as thesuper elastic material nitinol, platinum which may be but is not limitedto being used in neurovascular applications, silver which may provideantimicrobial properties, tantalum, niobium, and other super elasticmaterials such as copper-aluminum alloys. In some embodiments,individual layers of metal may be scanned using a directed high energybeam, such as a continuous or pulsed laser or e-beam system toselectively melt the powder, i.e., melt the powder in predeterminedlocations. Each layer, or portion of a layer, is scanned to create aplurality of predetermined porous or mesh physical constructs, and whennecessary predetermined solid constructs, by point exposure to theenergized beam. This leads to the production of linear, curvilinear, orother shaped struts that correspond to the segments described previouslyherein and eventually to a porous or mesh physical construct, as will bedescribed below. Successive layers are deposited onto previous layersand also are scanned. The scanning and depositing of successive layerscontinues the building process of the predetermined porous geometries.As disclosed herein, continuing the building process refers not only toa continuation of a porous or mesh physical construct from a previouslayer but also a beginning of a new porous or mesh physical construct aswell as the completion of the current porous or mesh physical construct.

In alternative arrangements, non-metallic materials may be used in suchALM processes. These materials may include implantable plasticsincluding but not limited to any one or any combination of wax,polyethylene (PE) and variations thereof, polyetheretherketone (PEEK),polyetherketone (PEK), acrylonitrile butadiene styrene (ABS), silicone,and cross-linked polymers; bioabsorbable glass, ceramics, and biologicalactive materials such as collagen/cell matrices. Composites of any oneor any combination of these materials or the metals described previouslyherein may be made as a combination with any one or any combination ofbone cement, bone, soft tissue, and cellular matrices and tissue cells.

A component structure or sub-structure thereof produced by theapproaches herein may be porous and if desired, the pores can beinterconnecting to provide an interconnected porosity. In someembodiments, the amount and location of porosity may be predetermined,and preferably lie in the range 50% to 90% as being suitable when usedas a bone ingrowth surface, and 20% to 90% as being suitable for polymerinterlock surfaces. This also applies to cases where the outer poroussection of a medical device is connected to host bone with bone cementor bone type adhesives for example.

When physical constructs are produced using a laser or electron beammelting process, a prefabricated base or core may act as a substratebuilding physical constructs. Such bases may be made of any one or anycombination of the materials described previously herein for use in theALM processes. In some instances, such materials may be different thanthe materials for the successive layers built during the ALM processes.Thus, a mixture of desired mixed materials can be employed. By way ofexample, porous layers can be built onto an existing article, whichitself may be porous or solid and may be made from any one or anycombination of cobalt and its alloys including a cobalt chrome alloy,titanium or its alloys, magnesium and its alloys, stainless steel,nickel and its alloys including a nickel titanium alloy such as thesuper elastic material nitinol, platinum, silver which may provideantimicrobial properties, tantalum niobium, and other super elasticmaterials such as copper-aluminum alloys. In this example, the existingarticle may be an orthopaedic implant. In such a manner, the approachesdescribed herein may be exploited to produce commercially saleableimplants with bone in-growth structures having porous surfaces with apredetermined scaffold structure. The constructed medical implant, whichmay correspond to the mesh geometries described previously herein, mayhave a porosity and architecture optimized to create very favorableconditions so that bone in-growth takes place in a physiologicalenvironment and the overall outcome favors long-term stability.

Because a laser or electron beam melting process may not requiresubsequent heat treatment or the temperature at which this heattreatment occurs is lower than any critical phase change in thematerial, the initial mechanical properties of any base metal to which aporous structure is applied may be preserved.

The equipment used for additive layer manufacturing of implants could beone of many currently available, including but not limited to thosemanufactured by Renishaw, SLM Solutions, Realizer, EOS, Concept Laser,Arcam and the like. The laser or electron beam also may be acustom-produced laboratory device.

As shown in FIG. 6 , mesh sheet 150 was produced by melting successivelayers of metal powder. To produce physical constructs of this form,with reference to FIG. 3 , spots corresponding to ends 111 ofcurvilinear segments 110 and ends 122 of curvilinear segments 120 may beformed during production of one layer of an intended physical structurecorresponding to porous CAD volume 100A, spots corresponding to ends 121of curvilinear segments 120 and ends 112 of curvilinear segments 110 maybe formed using a high energy beam during production of another layer ofthe intended physical structure corresponding to porous CAD volume 100A,and spots corresponding to portions of curvilinear segments 110 andportions of curvilinear segments 120 may be formed during production ofother layers of the intended physical structure corresponding to porousCAD volume 100A. Such spots may be formed using an SLS or SLM process inwhich when a laser is the high energy beam, the powder particles mayhave a diameter on the order of between and including 5 and 50 μm, andwhen an electron beam is the high energy beam, the powder particles mayhave a diameter on the order of between and including 75 and 150 μm. Ina similar manner, the geometries of the porous CAD volumes 100, 200A,and 200B as described previously herein may be formed into mesh sheets.Similar constructions may be but are not limited to being formed usingany one or any combination of the other additive manufacturing processesdiscussed previously herein, including 3DP, SLA, FFF, and digital lightprocessing (DLP).

Again referring to FIG. 6 , mesh sheet 150 is made of titanium. Due tothe rigidity of the material, mesh sheet 150 has been trimmed to size bya pair of scissors, producing little debris relative to other devicesthat require modification from a Midas Rex, such as with cone and sleeveaugments. Mesh sheet 150 is malleable due to its minimal thickness andthus has been curled into shape. As shown, mesh sheet 150 has also beencoated with a PERI-APATITE® hydroxyapatite coating but remains porous topromote bone in-growth. Although the surfaces of mesh sheet 150 arerelatively rough, in alternative arrangements, at least one surface ofthe mesh sheet may be smooth to prevent irritation to surrounding softtissues. Such surface may be produced using the techniques taught in the'010 Patent incorporated by reference in its entirety herein.

Referring to the illustrations of FIGS. 7A-7D, the CAD modeling andlayered additive manufacturing process in accordance with the presenttechnology can be used to form physical structures having a plurality ofmesh sheets 350A, 350B, 350C, 350D connected together by one or morelinks 355. The mesh sheets may be but are not limited to being formed ofsegments corresponding to segment geometries of porous CAD volumes, suchas but not limited to any one or any combination of porous CAD volumes100, 100A, 200A, and 200B or may be formed of a series of overlappingand underlapping strips prepared using a CAD model without the use ofrepeating unit cells, as described previously herein. During preparationof any such woven mesh patterns, the overlapping and underlappingsegments or strips may be fused together at selected intersections or“cross-over” areas of the strips to impart more rigidity to the mesh atthe fused areas.

In such arrangements, the physical mesh sheet constructs may have butare not limited to having a square profile such as in FIG. 7A, arectangular profile such as in FIG. 7B, a circular profile such as inFIG. 7C, and a triangular profile such as in FIG. 7D. Links 355, whichmay correspond to link geometries created within a CAD model, may haveclosed perimeters as shown, or may have open perimeters. Links 355 mayhave profiles which may be but are not limited to being circular,triangular, hexagonal, and octagonal. As in the examples of FIGS. 7A-7D,links 355 may extend through openings defined by adjacent segments orstrips along edges of physical mesh sheet constructs, such as meshsheets 350A-D.

When forming such physical structures using any layered additivemanufacturing process, a predetermined thickness of mesh sheets 350A,350B, 350C, 350D and of links 355, corresponding to a slice height of aCAD model inputted into a layered additive manufacturing device, may begenerated during production of a single layer of an intended physicalstructure. In this manner, a portion of each of mesh sheets 350A-350Dand of each of links 355 shown in FIGS. 6A-6D may be produced duringformation of a single layer of the physical structures shown in FIGS.7A-7D.

There are a number of useful applications for the mesh sheets. As shownin FIG. 8 , mesh sheet 150 is in the form of a foil such that the meshsheet may be press fit into a bony void space, such as that shown inbone 1. As shown, mesh sheet 150 has a coated outer surface thatpromotes mechanically strong bone in-growth and also has a coated innersurface that provides a textured surface to rigidly fix bone cement,when such cement is applied to the inner surface, in the shape of theinner surface of the mesh sheet. For this type of application, meshsheet 150 has a maximum allowable pore size to prevent seepage of thecement through the mesh sheet causing undesirable bone-to-cementcontact. Below a specific pore size, bone cement is at its “doughphase,” a phase in which the cement is viscous enough such that thecement does not to stick to a surgeon's glove and does not penetratethrough the mesh. Randomizing the unit cell structures within a porousCAD volume may also limit the flow of bone cement.

As shown in FIGS. 9A and 9B, a CAD model of mesh sheet geometry 450includes a set of connected link geometries 455A oriented in a verticaldirection and link geometries 455B oriented in a horizontal direction. A“chain link” mesh sheet corresponding to this CAD model including a setof connected links may be formed using any one or any combination of theALM processes described previously herein in accordance with the presenttechnology.

As shown, each link geometry 455A, 455B is a substantially planar openhexagon formed of six connected segments 410 which are connected to aplurality of other link geometries 455A, 455B. Each link geometry 455A,455B has a closed perimeter such that a physically produced linkcorresponding to this link geometry may not be separated from otherlinks to which the physically produced link is connected withoutsevering one of the connected links. In alternative arrangements, atleast some physically produced links may have an opening through theirperimeters such that links to which a link is connected may be removedthrough the opening. In instances in which the opening of an openperimeter is too small, a link having such an opening may be deformablesuch that the opening may be either one or both of widened and narrowed.

In one arrangement of forming mesh sheet geometry 450, each linkgeometry within a CAD model may be modeled individually without the useof tessellated unit cells. In an alternative arrangement as shown in theexample of FIG. 9C, unit cell 405 may be tessellated to form mesh sheetgeometry 450. As shown, unit cell 405 includes one link geometry 455Ainterlocked with one link geometry 455B. With reference to FIGS. 9A and9B, upon tessellation of unit cell 405 to form a porous CAD volumecontaining mesh sheet geometry 450, each link geometry 455A of one unitcell becomes interlocked with link geometries 455B of adjacent unitcells, and each link geometry 455B of one unit cell becomes interlockedwith link geometries 455A of adjacent unit cells. In this manner, in theexample of FIGS. 9A and 9B, each link geometry 455A becomes interlockedwith four link geometries 455B and each link geometry 455B becomesinterlocked with four link geometries 455A.

In the example of FIGS. 9A and 9B, planes defined by a widest dimensionof interlocked link geometries 455A, 455B are arranged orthogonally toeach other. Interlocked link geometries 455A, 455B are spaced apart aslight distance from each other and have the same size. In alternativearrangements, interlocked link geometries may be set at anynon-orthogonal angles to each other, different spacings relative to eachother, and different sizes relative to each other. Through thesevariations, either or both of the porosity and flexibility of meshsheets corresponding to modeled mesh sheet geometries may be varied. Insome alternative arrangements, unit cells, such as unit cells 405, maybe offset by a distance that is different than the spacing betweeninterlocked link geometries of each unit cell to form a non-uniform meshgeometry. In some alternative arrangements, some regions of a meshgeometry may be different in any dimension than other regions of a meshsheet geometry to form varying porosity, which may be a gradientporosity, within a mesh sheet corresponding to the mesh geometry.

When forming a physical structure corresponding to mesh sheet geometry450, which may be a mesh sheet or other flexible construct such as thoseshown in FIGS. 12A and 13B described further herein, a bottom portion oflinks, such as a bottom portion of a link corresponding to vertices 456of link geometries 455A, may be formed during preparation of a firstlayer of the physical structure of the mesh sheet geometry by an ALMdevice, such as any one or any combination of the equipment discussedpreviously herein. Successive layers of the physical structure may thenbe prepared by the ALM device to form complete links corresponding tolink geometries 455A, 455B in which, immediately upon completion of thelinks, links corresponding to link geometries 455A define planes thatare aligned vertically, i.e., orthogonally, with respect to a substrate,which may be a build platform or other component structure, on which thephysical structure is formed, and links corresponding to link geometries455B define planes that are aligned horizontally, i.e., parallel, withrespect to the substrate. In this manner, and with reference to FIG. 9B,during preparation of the successive layers, only portions of linkscorresponding to width 457 along opposite sides of thevertically-aligned hexagonal links 455A may be formed in the layersforming links corresponding to horizontally-aligned hexagonal links455B. In an alternative arrangement, a portion of a plurality of linkscorresponding to vertices 456 of both link geometries 455A, 455B may beformed during preparation of a first layer of the physical structure ofthe mesh sheet geometry by an additive manufacturing device. In such anarrangement, successive layers of this physical structure then may beprepared by the ALM device to form the complete links corresponding tolink geometries 455A, 455B in which, immediately upon completion of thelinks, links corresponding to link geometries 455A define planesextending at a nonparallel and a non-orthogonal angle, such as but notlimited to an angle of 45 degrees, with respect to the substrate onwhich the physical structure is formed, and links corresponding to linkgeometries 455B define planes also extending at a nonparallel andnon-orthogonal angle to the substrate, which may be the same angle asthe planes defined by the links corresponding to link geometries 455Aextend with respect to the substrate, but in an opposite direction asthe links corresponding to link geometries 455A extend.

The size of the segments forming the links, which correspond to thesegment geometries forming the link geometries, such as link geometries455A, 455B, the shape of any number of the segments and any number ofthe links, and thus the sizes of pores defined by the links may beadjusted to suit a particular application of a physical construct suchas a mesh sheet. Such variables may be used to control flexibility,range of motion, and strength of an overall construct such as a meshsheet, as well as to control either or both of the amount of tissueingrowth and the egress of contained materials, with pore size and shapeoptimized to pressurize doughy bone cements or morselized bone graftmaterials. To achieve these goals, the pore sizes preferably should begreater than 300 μm and strut sizes preferably should be greater than100 μm. In this manner and depending on material choice, the physicalconstruct may have any one or any combination of a relatively hightensile strength, low flexion and compressive stiffness, variabletensile stiffness, variable stiffness, and ductility.

Any link geometry, and thus the corresponding link in a physicalconstruct, may be but is not limited to being in the shape of a hexagon,a circle, an ellipse, a square, a triangle, a rectangle, and anycombination of these shapes. Links may be planar, such as linkscorresponding to link geometries 455A, 455B in the example of FIGS.9A-9C, as well as non-planar, in which links may extend in threedimensions, e.g., a kinked hex or quadrilateral design. In somearrangements, the ratio of strut size to pore size for a given shape ofstrut corresponding to a segment in a CAD model may be varied toinfluence flexibility, range of motion, and strength in some or alldirections. The ratio of links connected to each link may be adjustedthroughout all or a portion of a flexible construct such as a meshsheet. For example, in a preferred arrangement, a connected link ratioof 4:1 may be used to make a uniform sheet construct. In anotherexample, a connected link ratio of 2:1 may be used to make a chainconstruct, and in yet another example, odd-numbered connected linkratios may be used to create discontinuous flexible constructs.

Physical constructs formed using link geometries may have a variableporosity, which may be but is not limited to being a graded porosity, byvarying either or both of link size and shape within the same constructto provide for any one or any combination of variable flexibility,variable range of motion, and variable strength throughout theconstruct. In some arrangements, physical constructs formed using thelink geometries may be formed with anisotropy by varying either or bothof link size and shape, by varying strut size and shape, or byselectively fusing some links to each other. Links may be coated withvarious biocompatible substances, such as but not limited tohydroxyapatite, to facilitate biological bone ingrowth. Links also maybe coated to minimize wear and also with antibiotic eluting coating inorder to treat infection.

Following formation of a flexible construct such as chain link meshconstructs, mechanical and flexural properties may be adjusted byvarious post-processing techniques. In one arrangement, the flexibleconstruct may be rolled into a cylinder, increasing the yield strengthof the construct along the axis of the cylinder. In another arrangement,one flexible construct may be stacked onto or nested within anotherflexible construct such that the stacked or nested constructs interactto constrain or augment each other. In some applications, the flexibleconstruct may be shaped, such as by rolling or flattening, such that theconstruct does not transmit compressive loads.

As shown in FIGS. 10A-10C, in one application of the chain link meshsheets, mesh sheet 450A, which has been formed using an ALM processbased on a mesh sheet geometry substantially similar to mesh sheetgeometry 450, acts as a trochanteric gripper which may be placed overthe trochanter of a femur to provide an ingrowth surface. Shell 440 isthen placed over mesh sheet 450A and around the trochanter. Cables 15,which as shown are cerclage wires, may be wrapped around mesh sheet 450Ato hold mesh 450A in place or, alternatively, may be wrapped aroundshell 440, such as by being passed around or through a thickness ofspaced-apart arms of shell 440, to hold the assembly of the shell andmesh sheet 450A in place.

Referring now to FIGS. 11-17D, the chain link and mesh sheets may beproduced along with additional features by any one or any combination ofthe ALM processes described previously herein. As shown in FIG. 11 ,mesh sheet 550 includes a woven mesh pattern 551 and an alphanumericpattern 552 fused to the woven mesh pattern, in which the alphanumericpattern is formed substantially as shown and described in the '010Patent, using an ALM device. During preparation of mesh sheet 550,successive layers are added to basic mesh pattern 551 to formalphanumeric pattern 552. In this manner, alphanumeric pattern may beused as product identifiers.

As shown in FIGS. 12A-12C, mesh sheets may include porous attachmentcomponents. In the example of FIG. 12A, mesh sheet 650A includes chainlink pattern 651A and a porous attachment component 652A fused to thechain link pattern at spaced-apart regions of the chain link pattern. Inthe example of FIGS. 12B and 12C, mesh sheet 650B includes woven meshpattern 651B and porous attachment component 652B. In these examples,porous attachment components 652A, 652B have been added to both sides ofwoven mesh pattern 651B during an ALM process. Porous attachmentcomponents may be lattice structures such as those disclosed in the '332Publication as in the example shown, or may be in the form of woven meshor chain link patterns. In applications for facilitating biologicalattachment of bone, porous attachment components, such as porousattachment components 652A, 652B, may be used and may have a pore sizein the range of approximately 100-1000 μm and a porosity whichpreferably may be at least 50%. Porous attachment components designed tofunction as scaffold cells for biological regeneration preferably mayhave a pore size greater than 100 μm and a porosity greater than 55%. Inalternative arrangements (not shown), porous attachment components maybe other types of porous structures including but not limited to wovenmesh or chain link mesh structures, which may have a pore size andporosity that is different than the mesh, chain link pattern, or otherpattern, which may be porous or non-porous, to which the porousattachment components may be attached.

As shown in FIG. 12C, mesh sheet 650B, acting as a foil, may be rolledinto a cylindrical shape and placed or pressed into a bony void space,such as in the base of a tibia bone 1, as in this example. Although notshown, mesh sheet 650A could be placed into a bony void space in asimilar fashion. In such arrangements, bone cement then may be addedinside of the cylindrically-shaped mesh sheets 650A, 650B. In thismanner, mesh sheets 650A, 650B may promote better mechanical rigiditybetween live bone and bone cement.

As shown in FIGS. 13A and 13B, physical eyelet 760 may be integratedinto the mesh sheets, chain link mesh sheet 750 in this example, duringan ALM process. Eyelet 760 may be modeled as solid eyelet geometry 760Aas shown in FIG. 13A having inner perimeter 761A, which may act as athrough bore. Depending on the parameter settings of the ALM device,eyelet 760 may be substantially solid or somewhat porous through itsthickness, upon production of the physical structure of the eyelet, asshown in FIG. 13B. Mesh sheet 750 was built in its entirety in layersusing an ALM process. As shown, some of hexagonal links 755 of meshsheet 750 abut outer perimeter 762 of eyelet 760. Some of such links 755have open perimeters in which ends of the open perimeters of the linksare fused to eyelet 760. Eyelet 760 may be but is not limited to beingused for screw, wire, or cable attachment of mesh sheet 750 to otherobjects, such as bone or other tissue.

Referring to FIG. 14A, a CAD model includes mesh sheet geometry 850including stud geometry 860, which as shown may be a rivet, which may beused to prepare a corresponding mesh sheet with a corresponding stud.The stud corresponding to stud geometry 860 may be formed in the samemanner as eyelet 760 and thus may be substantially solid or somewhatporous through its thickness and may be fused to links, with theexception that the stud may include a spike, corresponding to spikegeometry 863, and may not include any type of through bore. Such studsmay allow the construct to be press fit to itself or other materials,including bone. In some alternative arrangements (not shown), a studgeometry may include a through hole.

In FIG. 14B, a mesh sheet geometry 850A generated in a CAD modelincludes a plurality of stud geometries 860A extending outwardly near anedge of the mesh sheet geometry which may be used to prepare acorresponding mesh sheet with a corresponding stud. As shown in FIG.14C, each stud geometry 860A includes a lower base geometry 861A, anupper base geometry 862A, and an intermediate section geometry 863Abetween the lower and upper bases. The stud corresponding to each studgeometry 860A may be fused to the rest of the mesh sheet correspondingto mesh sheet geometry 850A at a lower base corresponding to lower basegeometry 861A, which may be porous, substantially solid, or solid.Referring again to FIG. 14B, studs corresponding to stud geometries 860Amay be formed, such as by an ALM process as described previously herein,on opposing ends of a mesh sheet corresponding to mesh sheet geometry850A such that a cable may be wrapped around an intermediate section ofa stud corresponding to stud geometry 860A. In this manner, such a meshsheet may be tensioned to form a rolled construct, which in somearrangements may be used to enclose other materials, such as but notlimited to bone graft material.

Referring to FIG. 15 , a hook may be added to the perimeter of a link asdemonstrated by hook geometry 965 attached at a vertex of hexagonal linkgeometry 955 at an outer perimeter of mesh sheet geometry 950. As shown,hook geometry 965 is in the form of a hexagonal link geometry having anopening at its perimeter. When prepared as a physical structure, themesh sheet corresponding to mesh sheet geometry 950 may be attached bythe hook corresponding to hook geometry 865 to other materials,including but not limited to biological and manufactured materials, ormay be attached to another portion of mesh sheet itself to form a wrapor covering.

As shown in FIG. 16 , mesh sheet 1050 includes a plurality of porousattachment components 1052 and eyelets 1060 fused to chain link meshpattern 1051. Other combinations of features including but not limitedto woven mesh patterns, chain link mesh patterns, porous attachmentcomponents, and eyelets may be combined into single mesh sheets inaccordance with the present technology. In some arrangements, mesh sheet1050 may be used in applications designed to facilitate biologicalattachment of soft tissue, including muscles, tendons, and ligaments. Insuch arrangements, the porous attachment components preferably may havea pore size greater than 100 μm and a porosity greater than 55%. Usingcomponents designed to facilitate attachment of a construct, such as thecomponents described with respect to FIGS. 13A-16 , the flexibleconstructs such as the mesh sheets described herein may be folded andattached to other media or to themselves to form a cavity that can beexpanded with a flowing material such as but not limited to bone cementor a combination of bone cement and another device, such as but notlimited to a hip or knee replacement, to fill a free-form bone defect.

Referring now to FIGS. 17A-17C, chain link mesh sheets provide a networkof links that form structures that are both porous and highly flexible.As in the example of FIG. 17A, mesh sheet 1150A may be folded to fill abony void cavity. As in the examples of FIGS. 17B and 17C, mesh sheets1150B and 1150C are positioned such that a middle portion of the sheetis substantially flat and an outer portion of the sheet is draped orextended around another object. Components employing the mesh sheet orflexible constructions described previously herein may be completelymanufactured in situ or may be partially manufactured for lateradjustment in the field to tailor the construct as needed. In someexamples, their flexible construction allows the mesh sheets to befolded to contain another material such as bone cement or morselizedbone graft where the composite structure of the mesh sheet and thecontained material exhibits modified mechanical properties, e.g.,enhanced rigidity when bone cement is added.

Referring now to FIGS. 18A and 18B, integrated mesh sheet 1250, which asshown may be termed a “strut graft,” was produced using an ALM processsuch as those described previously herein. Mesh sheet 1250 includesspaced-apart first porous regions 1270 along an entire length of themesh sheet, spaced-apart second porous regions 1275 across an entirewidth of the mesh sheet except at the locations of the first porousregion 1270, and third porous regions 1280 in all other sections of themesh sheet. In the example shown, each of porous regions 1270 and 1275is in the form of chain link mesh patterns, as described previouslyherein, and has a different porosity and pore size than the otherregions. As in the example shown, third porous regions 1280 may have arelatively low porosity such that the third porous regions aresubstantially rigid. First porous regions 1270 may have the highestporosity among the porous regions 1270, 1275, 1280 such that the firstporous regions 1270 of mesh sheet 1250 are the most flexible of theporous regions. In this manner, as shown in FIG. 18B, mesh sheet 1250may be bent about first porous regions 1270 such that the mesh sheet maybe wrapped around bone 10 to aid in bone repair. Second porous regions1275 may have a higher porosity than third porous regions 1280 but alower porosity than first porous regions 1270 allowing for third porousregions 1280 to be bent about second porous regions 1275 as well as forcompression of mesh sheet 1250 along the second porous regions such thatthe second porous regions may provide a groove within the mesh sheetwhen compressed. In this manner, with reference to the radiograph ofFIG. 18C, cables 15, which as shown are cerclage wires, may be wrappedaround second porous regions 1275 of mesh sheet 250 such that the secondporous regions are compressed to hold the mesh sheet tightly against thebone and to form a groove to hold the longitudinal location of thecables.

In some alternative arrangements of mesh sheet 1250, holes, which may bethreaded, may be provided within third porous regions 1280. In thismanner, fasteners may be inserted into third porous regions 1280 tofacilitate attachment of mesh sheet 1250 to large bone fragments. Insome alternative arrangements of mesh sheet 1250, any one or anycombination of the first, second, and third porous regions may be in theform of other porous patterns, such as lattice structures disclosed inany one or any combination of the '332 Publication, the '901 Patent, the'703 Patent, the '374 Patent, and the '010 Patent.

Referring now to FIGS. 19A-19E, mesh sheet 1350 is substantially in theform of a woven mesh sheet pattern similar to the patterns describedpreviously herein, which may be produced using ALM techniques such asthose also described previously herein. As shown in FIGS. 19A and 19B,mesh sheet 1350 includes rounded central pocket 1358 extending from flatregion 1359 of the mesh sheet. As shown in FIG. 19C, stamp 1385, whichas shown is a tibial base stamp, includes handle 1386 andsemicylindrical base 1387 having bottom surface 1388 that issubstantially flat. With reference to FIGS. 19D and 19E, stamp 1385 maybe pressed into mesh sheet 1350 to form a cavity in the mesh sheet. Dueto the flexibility of mesh sheet 1350, central pocket 1358 may bestretched such that the mesh sheet has substantially the same form assemicylindrical base 1387 of stamp 1385.

As shown in FIGS. 20A and 20B, in an alternative arrangement, stamp 1485having protrusions 1489 extending from substantially flat bottom surface1488 of the stamp may be used to press out central pocket 1358 of meshsheet 1350. In this manner, corresponding protrusions 1490 may be formedon a bottom of central pocket 1358.

As shown in FIG. 21 , in one application, stamped mesh sheet 1350 may beplaced into a burred out cavity of a bone, such as a tibia 2 as shown,and adhered to the cavity. In this manner, mesh sheet 1350 provides asurface for bone ingrowth to strengthen the mechanical engagement of thebone and bone cement applied into the stamped central pocket 1358 of themesh sheet and thus aids in preventing subsidence of an onlay or inlayimplant placed onto the bone cement and mesh sheet combination withinthe bone cavity.

There are still other useful applications of the mesh sheet flexibleconstructs.

Referring now to FIGS. 22A and 22B, tube device 1500 includes main tube1510 in the form of a trunk and secondary tube 1520 intersecting themain tube in the form a branch extending from the trunk. The tube devicemay be but is not limited to being part of a vascular stent on amicroscale or a garden hose on a larger scale. Tube device 1500 isporous, although the device may be coated, e.g., by a drug-eluting stentcoating or a plastic coating, or may be covered, e.g., by a thin plasticsheath. In some arrangements, the coating or covering may substantiallyconform to the outer surface of the tube device.

In this example, tube device 1500 includes a collection of tessellatedsegments 1505 corresponding to segment geometries within a CAD model ofthe tube device in the same manner such segments correspond to segmentgeometries as described previously herein and as described in U.S.patent application Ser. No. 14/969,695, the disclosure of which ishereby incorporated by reference herein. In this example, segments 1505of tube device 1500 are linear but have a sufficiently high density suchthat main tube 1510 and secondary tube 1520 have substantially circularcross-sections along their lengths. For some applications such as forvascular stents, segments 1505 may have a diameter of less than 200 μm,and more preferably may have a diameter in the range from 10 μm to 150μm. The amount of circularity of the cross-sections is dependent on thediscretization of the produced segments in preparing the segmentgeometries within the corresponding CAD model. In this manner, a greaternumber of shorter segment geometries will provide for greatercircularity for a given tube device to be produced than a lesser numberof longer segment geometries. In alternative arrangements, as describedpreviously herein, the segments may be curved to improve the circularityof the cross-sections of the main and secondary tubes.

As best shown in FIG. 22A, tube device 1500 is reticulated in the formof a substantially uniform mesh. In this configuration, opposing ends ofsets of four uniform segments 1505 intersect at their vertices to formquadrilateral pore cells 1525 substantially in the form of diamonds. Atthe intersection of main tube 1510 and secondary tube 1520, the maintube and the secondary tube share segments to create a smooth transitionbetween the main tube and the secondary tube. In alternativearrangements, the segment geometries within a CAD model corresponding tothe segments of the main tube and the secondary tube may be manipulated,e.g., by being made shorter or longer as disclosed in the '010 Patent orby being curved, to smoothly blend the adjacent segment geometries ofthe main tube wireframe geometry and the secondary tube wireframegeometry within the CAD model of the tube device.

Tube device 1500 may be fabricated using any one or any combination ofthe ALM processes for fabricating the mesh sheets described previouslyherein. In one example, as shown in FIG. 22B, tube device 1500 may bebuilt on substrate 5, which may be a build a platform or anothercomponent structure which may be integrated with the tube device, usingan SLS, SLM, or EBM process. To reduce the effects of gravity during thebuild process, tube device 1500 may be built in a vertical directionalong a central axis of main tube 1510. As is apparent in FIG. 22B,during a build process in such a configuration, portions of main tube1510 and portions of secondary tube 1520 may be built simultaneouslywithin a number of the processed layers.

With reference to FIG. 23 , tube device 1500 may be fabricated byprocess 1600. At block 1610, a first layer of a plastic or metal powdermay be deposited onto a substrate. At block 1620, the deposited firstlayer of the powder is at least partially melted, such as by a laser oran electron beam using an SLS or an SLM process, at predeterminedlocations. At block 1630, successive layers of the plastic or metalpowder are deposited onto previous layers as the previous layers cool.At block 1640, each of the successive layers of the deposited powder isat least partially melted before a subsequent layer of such successivelayers is deposited. In this manner, a tube device including a firsttube and a second tube intersected with the first tube are formed.

In some alternative arrangements, the tube device may have a variableporosity, i.e., variable density, which may be but is not limited tobeing a graded porosity, by varying any combination of the size andshape of pore cells, i.e., constructed open cells, defined by the strutswithin the tube device to provide for any one or any combination ofvariable flexibility, variable range of motion, and variable strengththroughout the tube device. In some arrangements, the tube device may beformed with anisotropy in addition to being, or may otherwise beprovided with, other unique characteristics by varying any combinationof pore cell size and shape, strut size and shape, or by selectivelyfusing some pore cells to each other. For example, as shown in FIG. 24A,in one alternative arrangement, tube device 1500A may be the same astube device 1500 with the exception that tube device 1500A may includeopening 1540 providing a larger passageway than pore cells 1525 to thecentral lumen defined by the tube, that may act as a window. In thismanner, tube device 1500A may be weaker in the area around opening 1540than throughout at least a majority of the tube device. Opening 1540 maybe formed through the creation of a CAD model of tube device 1500 inwhich a set of porous geometries are removed or through the use of a CADmodel of a tube device created directly without such porous geometries.As shown, complete pore cells 1525 are formed around the entireperimeter of opening 1540.

As shown in FIG. 24B, in another alternative arrangement, tube device1500B may be the same as tube device 1500A with the exception that tubedevice 1500B may include fully dense region 1545, i.e., a solidstructure, in place of opening 1540. In this manner, tube device 1500Bmay be stronger within fully dense region 1545 than throughout at leasta majority of the tube device. Any one or any combination of openingsand fully dense regions may be used to any one or any combination ofprovide for alternative flow paths, e.g., to control blood flow paths,create anisotropic mechanical properties, and allow for patient-specificvascular architecture.

As shown in FIG. 24C, tube device 1500C maybe the same as tube device1500 with the exception that tube device 1500C may include opening 1549,which may be in the form of a slit, providing a larger passageway thanpore cells 1525 to a central lumen defined by the tube. Opening 1549truncates many of pore cells 1525 surrounding the opening. In thismanner, opening 1549 provides failure points within tube device 1500Cthat will fracture prior to other areas of the tube device under a givenload. More generally, such openings may create localized differences inthe mechanical properties of a given construct. Opening 1549 may beformed through the creation of a CAD model of tube device 1500 in whicha set of porous geometries are clipped, i.e., truncated, or through theuse of a CAD model of a tube device created directly without suchclipped porous geometries.

Referring now to FIG. 25 , tube device 1700 may be the same as tubedevice 1500 with the exception that tube device 1700 may include longsegments 1705 having a wavy pattern defined by linear sections 1706 andcurved sections 1707 in place of pore cells 1525. As shown, segments1705 fuse with adjacent segments at periodic intervals 1709 at adjacentcurved sections 1707. In alternative arrangements of tube device 1700,adjacent segments may be fused at adjacent curved sections at fewer orgreater intervals, including at all instances of adjacency of curvedsections of adjacent segments.

Referring to FIG. 26 , projections 1550 may be provided on segments 1505of a tube device, such as tube device 1500. Such projections may beconfigured to interface with host tissue or blood clots in order tobreak up such clots. Each projection 1550 may extend in any directionfrom any segment 1505 to which it is attached, including outwardly awayfrom the tube device, inwardly toward the center of the tube device, orwithin a respective pore cell 1525 defined by the segment to provide anobstruction in the pore cell. In some arrangements, a plurality of theprojections may extend from any one segment. In some arrangements,projections on a tube device may extend in different directions relativeto the segments to which they are attached. Any such projections may befabricated, such as by any one or any combination of the additivemanufacturing processes described previously herein, during thefabrication of the tube device.

Referring again to FIG. 22A, opposing ends of main tube 1510 of tubedevice 1500 are open and exposed whereas one end of secondary tube 1520of the tube device is open but surrounded by a side opening within maintube 1510. In an alternative arrangement, any open end of a tube devicemay be collapsible to neck down and close off the opening of the tubedue to the flexibility of the scaffold structure of the tube devicethrough the use of the pore cells. Referring to FIGS. 27A and 27B, anynumber of the openings of the tube device may be closed by an end plate,such as end plates 1560A, 1560B. In the example of FIG. 27A, end plate1560A of tube device 1500D is attached main tube 1510D of the tubedevice. End plate 1560A, shown in an open position, shares a pluralityof struts with main tube 1510D on one side of the main tube such thatthe end plate may be opened or closed. As shown, end plate 1560A may beformed of tessellated pore cells in a similar manner as tube device1500.

In the example of FIG. 27B, tube device 1500E is the same as tube device1500D with the exception that end plate 1560B, shown in a closedposition, is solid or substantially solid such that undesirable solidsor fluids, as may be required for particular application, may notpenetrate through the end plate. These end plates may be applied to thesecondary tube as well, both at the exposed opening as well as at theopening at the intersection of main tube 1510E and the secondary tube.In some alternative arrangements, the end plate, whether porous orsolid, may be attached around a perimeter of the main tube such that theend plate is always in a closed position. In some alternativearrangements, the end plate, again whether porous or solid, may beattached to any number of the tubes of the tube device by way of links,such as links 355 described previously herein.

Referring now to FIG. 28 , tube device 1500F is the same as tube device1500 with the exception that tube device 1500F includes radiopaquemarkers 1570 that are detectable during imaging, such as through the useof x-rays. As in this example, radiopaque markers may be formed bymelting deposited metal powder at predetermined locations, such aswithin or on formed segments such as segments 1505, during thefabrication of a tube device, such as by process 1600 describedpreviously herein. The metal powder to form radiopaque markers 1570preferably may be platinum which may be blended with other metal powderssuch as those described previously herein for use in the additivemanufacturing process. A predetermined amount of platinum may be useddepending on the desired level of radiopacity of the radiopaque markers.

As shown in FIG. 29 , tube device 1500G is the same as tube device 1500with the exception that tube device 1500G includes sensor system 1580extending along pore cells 1525. Sensor system 1580 includes firstinsulating layer 1582A, conductive layer 1585 physically separated andthus electrically insulated from tube device 1500G by the firstinsulating layer when the tube device is made of metal, and secondinsulating layer 1582B to electrically insulate the conductive layerfrom peripheral devices to the tube device that may be conductive.Conductive layer 1585 may be made of any combination of gold, copper,and platinum. First insulating layer 1582A and second insulating layer1582B may be made of dielectric materials.

Conductive layer 1585 may be an electrical trace that may be attached toa probe or other sensing device of the sensor system during use of thesensor system. For example, such sensing device may detect bloodpressure within the vascular system of a patient, and electrical signalsmay be transmitted by the sensing device through conductive layer 1585to a receiving unit that receives the electrical signal. In someinstances, the receiving unit itself may then transmit further signalsvia wire or wirelessly to other desired locations.

Sensor system 1580 may be located on the outside of tube device 1500G,as shown, inside the central lumen of the tube device, or may beembedded within layers of the tube device. Although only one is shown,multiple sensor systems 1580 may be used. In some arrangements, secondinsulating layer 1582B may not be applied and in arrangements in whichthe tube device is made of plastic or other nonconductive materials, thefirst insulating layer may not be applied.

With reference to FIG. 30 , in some arrangements, tube device 1500G maybe fabricated by process 1800. In a block 1810, a tube device is formed,such as using process 1600 described previously herein. In block 1820, afirst insulating layer is formed onto a previously fabricated portion ofthe tube device. The first dielectric layer may be a thin filminsulating layer that may be grown/deposited via a physical vapordeposition/evaporation process. In block 1830, a metal powder isdeposited on the first dielectric layer, which may be after at leastpartial cooling of the first dielectric layer. In block 1840, the metalpowder is at least partially melted, such as by a laser or an electronbeam using an SLS or an SLM process, at predetermined locations to forma conductive layer. In block 1850, a second dielectric layer is formedonto the formed conductive layer, which may be after at least partialcooling of the conductive layer. The second dielectric layer may beapplied in the same manner as the first dielectric layer.

In some alternative arrangements of any of the tube devices describedpreviously herein, any number of the tubes, such as either or both ofthe main tube and the secondary tube, may have a cross-section along atleast a portion of the length of such tubes that has a regular shapesuch as a circle, an ellipse, or a polygon, or may have a cross-sectionwith an irregular shape. In some alternative arrangements, any number ofthe tubes of the tube devices described previously herein may havevarying perimeters along their lengths, and in some such instances, maybe tapered. In some alternative arrangements, any number of the tubes ofthe tube devices described previously herein may include custom featuresconfigured for interfacing with other medical devices, such as but notlimited to a catheter, an endoscope, and a platinum wire. In somealternative arrangements, any number of the tubes of the tube devicesdescribed previously herein may be configured with various spacings andsizings of the segments to vary Poisson's ratio within part or all ofsuch tubes.

In some alternative arrangements of any of the tube devices describedpreviously herein, any number of the tubes, such as either or both ofthe main tube and the secondary tube, may include woven segments. Inproducing such segments, any one or any combination of the CAD modelsdiscussed previously herein with respect to FIGS. 2-4B may be utilized.

In some alternative arrangements of any of the tube devices describedpreviously herein, any number of the tubes, such as either or both ofthe main tube and the secondary tube, may be formed through the creationof CAD models based on patient-specific data obtained through imagescans using magnetic resonance imaging (MRI), computed tomography (CT)or microCT, or other known processes.

In some alternative arrangements, any of the tubes of the tube devicesdescribed previously herein may be fabricated to have specific surfacemicro-topologies to create desirable in vivo performance. Suchmicro-topologies that may be controlled preferably include anycombination of a variable surface roughness to influence flow dynamics,cell adhesion, and a surface area/volume ratio. Such topologies may beformed by varying fabrication process parameters, such as during an ALMprocess used to make the devices, or by post-processing techniques suchas acid etching which is described in greater detail in the '332Publication incorporated by reference previously herein, media blasting,heat treatment, electropolishing, thin film deposition, ion bombardment,or other known processes.

In some alternative arrangements, any number and any combination of theadditional features, e.g., the openings, end plates, projections, slits,radiopaque markers, etc. described with respect to the tube devices maybe applied to any particular tube device or to any of the other devices,such as the mesh sheets, described previously herein. Additionally, anyof the various features described with respect to the mesh sheets may beapplied to any of the tube devices described previously herein. Forexample, any number and any combination of the porous attachmentcomponents, eyelets, stud geometries which may act as rivets and whichmay include any combination of spike geometries and through holes, andhooks may be applied to the segments of the tube devices.

It is to be understood that the disclosure set forth herein includes allpossible combinations of the particular features set forth above,whether specifically disclosed herein or not. For example, where aparticular feature is disclosed in the context of a particular aspect,arrangement, configuration, or embodiment, that feature can also beused, to the extent possible, in combination with and/or in the contextof other particular aspects, arrangements, configurations, andembodiments of the invention, and in the invention generally.

Although the invention herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent invention. It is therefore to be understood that numerousmodifications may be made to the illustrative embodiments and that otherarrangements may be devised without departing from the spirit and scopeof the present invention as defined by the appended claims.

The invention claimed is:
 1. A method of forming a tubular structureincluding a first tube and a second tube comprising the steps of:successively depositing layers of a first material and at leastpartially melting at least a portion of each deposited layer of thefirst material at predetermined locations to form the first tube and thesecond tube, wherein the first tube defines a first central axis, hasfirst and second ends, and has a porous surface around a circumferenceof the first tube, wherein the second tube defines a second central axistransverse to the first central axis and is attached to the first tubeat an intersection such that the second tube is spaced from the firstand the second ends of the first tube and such that the second tube hasan end that is spaced from the first tube, and wherein at least oneportion of the first tube and at least one portion of the second tubeare formed by a single one of the steps of at least partially melting adeposited layer of the first material.
 2. The method of claim 1, whereinthe at least partially melting steps include forming portions of aplurality of segments, and wherein the formed segments of the pluralityof segments are attached to at least one other formed segment of theplurality of segments at vertices to define a plurality of open cells,the plurality of open cells forming a surface or surfaces of either oneor both of the first tube and the second tube.
 3. The method of claim 2,wherein some of the open cells are larger than some of the other opencells.
 4. The method of claim 2, wherein the at least partially meltingsteps form a fully dense region of the first material between open cellsof the plurality of open cells in the first tube.
 5. The method of claim4, wherein the fully dense region extends from the first tube to thesecond tube such that the fully dense region is also in the second tube.6. The method of claim 1, wherein the at least partially melting stepsinclude forming projections extending from either one or both of thefirst tube and the second tube.
 7. The method of claim 6, wherein atleast some of the projections are curved struts.
 8. The method of claim1, wherein the first end or the second end extends in a directiontransverse to the first central axis.
 9. The method of claim 8, whereinthe first end or the second end is solid and extends within and aroundan entirety of the perimeter of the first tube.
 10. The method of claim1, wherein either one or both of (i) the first tube has varyingcross-sections along a first tube length thereof, the cross-sections ofthe first tube defining a plane perpendicular to a central axis of thefirst tube, and (ii) the second tube has varying cross-sections along asecond tube length thereof, the cross-sections of the second tubedefining a plane perpendicular to a central axis of the second tube. 11.The method of claim 1, wherein each separate at least partially meltingstep to form the first tube forms a complete cross-section of the firsttube.
 12. The method of claim 1, further comprising the steps of:depositing an additional material different from the first material withor within at least one of the deposited layers of the first material;and at least partially melting at least a portion of the depositedadditional material at predetermined marker locations to form radiopaquemarkers, wherein the radiopaque markers, upon formation of the firsttube and the second tube, either one or both of (i) are at a surface ofeither one or both of the first tube and the second tube or (ii) extendfrom either one or both of the first tube and the second tube.
 13. Themethod of claim 12, wherein the additional material includes apredetermined amount of platinum corresponding to a desired level ofradiopacity of the radiopaque markers.
 14. The method of claim 1,further comprising the steps of: forming a first dielectric layer ontoan at least partially melted layer of the first material after at leastpartially cooling such partially melted layer; depositing a conductivematerial onto the formed dielectric layer; and at least partiallymelting at least a portion of the deposited conductive material atpredetermined conductive locations to form a patterned conductive layer,wherein the patterned conductive layer, upon formation of the first tubeand the second tube, is on or embedded in either one or both of thefirst tube and the second tube.
 15. The method of claim 1, wherein laterlayers of the successively deposited layers that have been at leastpartially melted are below earlier such layers relative to the ground.16. The method of claim 1, wherein at least partially melting stepsfurther form segments of the first tube and the second tube, thesegments being attached at vertices, wherein the second tube has aporous surface around a circumference of the second tube, wherein thefirst tube defines a first lumen therethrough and the second tubedefines a second lumen therethrough, and wherein the first tube and thesecond tube share some of the segments at the intersection such that thefirst lumen and the second lumen are in communication.
 17. A method offorming a tubular structure including a first tube and a second tubecomprising the steps of: depositing a first layer of a material onto asubstrate; at least partially melting at least part of the depositedfirst layer of the material at predetermined locations; depositingsuccessive layers of the material onto previously deposited and at leastpartially melted layers of the material; and at least partially meltingat least part of each of the successive layers of the material atadditional predetermined locations to form the first tube and the secondtube such that the first tube defines a first central axis, has firstand second ends, and is intersected with the second tube defining asecond central axis transverse to the first central axis such that thesecond tube is spaced from the first and the second ends of the firsttube and such that the second tube has an end that is spaced from thefirst tube, wherein the first tube has a porous surface around acircumference of the first tube, and wherein at least one portion of thefirst tube and at least one portion of the second tube are formed by asingle one of the steps of at least partially melting a deposited layerof the material.
 18. The method of claim 17, wherein at least partiallymelting steps further form segments of the first tube and the secondtube, the segments being attached at vertices, wherein the first tubedefines a first lumen therethrough and the second tube defines a secondlumen therethrough, wherein the second tube has a porous surface arounda circumference of the second tube, and wherein the first tube and thesecond tube share some of the segments at the intersection such that thefirst lumen and the second lumen are in communication.
 19. A method offorming a tubular structure including a first tube and a second tubecomprising the steps of: successively depositing layers of a firstmaterial and at least partially melting at least a portion of eachdeposited layer of the first material at predetermined locations to formthe first tube, wherein the first tube defines a first central axis;successively depositing layers of the first material or a secondmaterial and at least partially melting at least a portion of each ofthe deposited layers of the first material or the second material atadditional predetermined locations to form the second tube, wherein thesecond tube defines a second central axis transverse to the firstcentral axis and is attached to the first tube at an intersection;forming a first dielectric layer onto an at least partially melted layerof either one or both of the first material and the second materialafter at least partially cooling such partially melted layer; depositinga conductive powder material onto the formed dielectric layer; and atleast partially melting at least a portion of the deposited conductivepowder material at predetermined conductive locations to form apatterned conductive layer, wherein the patterned conductive layer, uponformation of the first tube and the second tube, is embedded in eitherone or both of the first tube and the second tube.
 20. The method ofclaim 19, wherein the first material and the second material are thesame material.